Shouldn't be really loose. There should be cross pieces @ the top from the bar to the top of the grill that minimize shaking, and when those are off, (there is a tab), the bar has some front/back movement. The bar shouldn't shift a lot up and down though, that would indicate that maybe the bolts under those for circle covers on the front are a little loose.
Hint, 9/10 times the techs don't aim and tighten the lamps, so those move really easy. To tighten them, there is a rectangular cover @ the top of the lamp with the logo, pop it off and there is a hole. Stick a very large phillips in there to mesh with the gear you can see from the back and turn one way to tighten, the other to loosen. (It may take a couple different drivers to find the right one that meshes).